merged latest and some updates:
1) add 'lang' filed to Status class 
2) change MaximumHitFrequency to GetSleepTime to avoid rate limit 
2) modify GetFollowers, GetFollowerIDs, GetFriends, GetFriendsIDs using
GetSleepTime method
Merge branch 'master' of https://github.com/bear/python-twitter.git into wenyi
Merge remote-tracking branch 'origin/master' into wenyi

Conflicts:
	twitter.py
merge and clean up

add GetAVerageSleepTime function
Merge pull request #96 from bear/wenyi

lang in Status, new rate limit control